Could use some help here. I believe my fuel pump is starting to whine. I have a high pitched whine toward the left rear of car that sounds like fuel pump noise. Coming from what appears to be behind the seat higher up in the car.

1.) Is the pump located internal tothe tank or is it external?
2.) After looking at different pumps it appears there are several types?

I have a 2000, CLK430 and need to resolve this issue. Any help would be appreciated.

Mark

 

pretty sure it's on the right rear underneath the car (external pump). If it is higher up, sounds inside the car, make sure it's not a pse pump

 

Would you mind elaborating a bit more on the PSE pump. I'm not sure what a PSE pump is? Thanks for the info.

 

pse stands for pneumatic systems equipment, controls the locking system and the logic of the alarm system. The door locks are vacuum actuated, the pse is the pump which generates the vacuum for operation. But tell me, is this car a cabriolet/convertible? If so, I have had the relay for the top pump stick numerous times, causing pump run-on. would be behind the center/left rear seat area, and will hear it in the trunk too.

 

MB,
The PSE sounds like the culprit. It is high up and behind the left rear seat. I am assuming it is working somewhat properly due to the fact my doors lock and the alarm seems to set?! It does get prettynoisy when it runs though.

1.) Does the system maintain a vacumn all the time or does it run just when needed (locking etc)? My pump seems to run a lot. (It does seem to cycle every once in a while.)

2.) Also where is the relay located?

 

to check if it is the pump, lock yourself inside the car and hit the lock/unlock button numerous times with the key off and see if the noise is present. if so, it's the pse. I am assuming you have the cabriolet because you are interested in the location of the relay I mentioned. From inside the trunk, there is the carpet towards the rear backrest area. the access port for the pressure release on the top pump is there, closer to left than right (see operator manual). lift the carpet up and look around the area of that allen release and there will be a black relay which is behind the partitian covering but accessible if you are careful without removing the big metal covering. You can also just look at the fuse chart for the soft top hydraulic pump and remove the fuse. Probably a 40 amp fuse, likely in the trunk fuse box on the right side , behind battery, under carpet. Fuse would be easiest. the fuse chart is located in the front fuse box on the driver side engine compartmen t and the other is at the right rear underneath the carpet. Both are on the backsides of the fuse box cover.